Linear motors and planar motors are now widely used in many manufacturing fields such as components insertion, integrated-circuits fabrication, precision metal-cutting, etc. U.S. 2003/0102721 A1, U.S. Pat. No. 6,650,079 B2, U.S. Pat. No. 6,548,917 B2, U.S. Pat. No. 6,486,941 all have an X-Y table which consists of a plurality of magnets. For always keeping an air-gap between the surface of said magnets and the rotor, the most of said prior arts should be equipped with an air cushion therebetween. None of them can prove to work in very high accuracy (e.g. 0.001 mm) in their patents. In fact, the working accuracy is depending upon the precision of the components such as the magnets, the base structure, the coils layout, etc. In order to achieve high accuracy, the plurality of magnets, the air-gap system, and the base geometry should be manufactured to very accurate sizes. These requirements, together with the complex layout structure, make these designs inflexible and difficult to adapt to the changing environments. For applications with different precisions or travel ranges, the overall motor structure has to be redeveloped.
The stator base of 2-D planar motor in the prior art needs to be crafted from a single slab of steel using high precision metal cutting machines or lasers. Alternatively, they have to “stick” small pieces of permanent magnets together to form a magnetic checker board. There is no mass manufacturing of the stator base. As a result, the overall cost of 2-D variable planar motors becomes prohibitively expensive.